The objectives of this project are to identify and describe environmental and host determinants of cancer in areas at high risk of cancer through the use of analytical epidemiologic and biometric techniques, particularly case-control studies of specific cancers. Completed during the year were case-control studies of esophageal cancer in coastal South Carolina, oral cancer in Atlanta, New Jersey, Los Angeles, and San Francisco, and laryngeal cancer in Texas. Analyses from South Carolina showed that esophageal cancer risk is strongly increased among heavy users of alcohol, especially moonshine, but that low intake of fruits and vegetables also contributes to elevated mortality From this tumor. In the four- center study, smoking and drinking tended to combine in a multiplicative fashion to enhance oral cancer, with heavy consumers experiencing more than 35-times the risk of abstainers. Several international studies are underway to take advantage of unique opportunities to evaluate diet and other factors, including air pollution, in the etiology of cancer. Smoking was shown to be the dominant cause of lung cancer among men in Shanghai, while exposures to cooking oil volatiles were implicated in the high risk of lung adenocarcinoma among women, most of whom were nonsmokers. Consumption of fermented pancakes, a preference for salty food, and smoking were related to the high risk of stomach cancer in Shandong China, while protective effects were found for vegetable intake. A case-control study of gastric cancer continued in areas of Italy that have among the world's highest rates of this malignancy. Also in operation is a randomized intervention trial in Linxian, China, to assess the role of vitamin/mineral supplementation on reducing the area's extraordinarily high cancer risk.